Kaposi’s Sarcoma | human herpes virus 8(HHV8) cancer

 Introduction and Epidemiology

Kaposi’s sarcoma (KS) is a tumor associated with Human herpesvirus 8 (HHV8), also known as Kaposi’s sarcoma-associated herpes virus (KSHV). 

Epidemiology.

KS is one of the most prevalent cancers in children in those regions of Africa with a high prevalence of HIV infection and is an AIDS defining illness.

It has been estimated that an HIV-infected individual has a 20,000 times increased risk of developing KS compared with people without HIV.

A lymphadenopathic form of Kaposi’s sarcoma is also seen in HIV seronegative pre-pubertal children.

In Kenya, childhood KS has an incidence rate 3.6 per million.

•   KS presents as a systemic disease with lymphadenopathy, cutaneous lesions, oropalatal and inguinoscrotal disease with or without internal organ involvement.

•    Skin lesions are reddish to dark purple multifocal and widespread.

They may be flat, raised or nodular. There is tendency to affect groins and genitalia.

Facial nodules commonly accompanied by peri-orbital oedema and haemorrhages while oral lesions tend to involve the hard palate, gums or tongue. 

•    Internal lesions may cause bleeding, intussusception, pain and weight loss and  respiratory system involvement may cause cough, shortness of breath, haemoptysis, chest pain or pleural effusions. 

 Diagnosis

•   KS presents as a systemic disease with lymphadenopathy, cutaneous lesions, oropalatal and inguinoscrotal disease with or without internal organ involvement.

•   Skin lesions are reddish to dark purple multifocal and widespread lesions.

They may be flat, raised or nodular. There is tendency to affect groins and genitalia.

Facial nodules commonly accompanied by peri-orbital oedema and haemorrhages while oral lesions tend to involve the hard palate, gums or tongue. 

•   Internal lesions may cause bleeding, intussusception, pain and weight loss and respiratory system involvement may cause cough, shortness of breath, haemoptysis, chest pain or pleural effusions. 

•   Biopsy and histology of lesion confirms the diagnosis. 

•   Other investigations may include bronchoscopy, endoscopy, Ultra scan (U/S) and CT scan 

•   Other supportive investigations include haemogram, urea, electrolytes and creatinine and LFTs.

Staging and risk assessment

HIV Screening Risk Assessment.

There is no accepted and validated system for staging all types of Kaposi’s sarcoma (KS) in  children. The AIDS Clinical Trial Group system was devised pre-HAART era.

It considers:

  •  The extent of the tumor,
  •  The status of the immune system (CD4 count),
  •  Presence or absence of systemic illness.  Under each of these, 2 subgroups identified by either a zero (0, or good risk) or a 1 (poor risk). 

Management

This depends on whether associated with HIV immunosuppression, number and location
of the tumors and symptoms.

 General and supportive treatment

  • • This includes the management of:
  • ~ HIV infection with antiretroviral drugs (may cause tumour regression)
  • ~ Anaemia, thrombocytopenia with blood and blood products
  • ~ Fever, co- infections (including TB) and pain.
  • ~ Poor nutritional state often present.
     

Specific treatment.

• Chemotherapy – for generalized or extensive disease the regimen of choice is a combination vincristine and bleomycin (BV). In those patients with extremely poor status, two drug or single drug regimen may be opted for.

• Few small localised lesions may be treated with cryotherapy alone where available and Radiation therapy used for limited localized disease or for palliation.
 

Response Evaluation and Follow-up.

• Response to HIV treatment with HAART usually improves the outlook of HIVassociated Kaposi’s sarcoma (KS). Reductions in size and number of lesions are evidence of response to treatment. Activity and well-being should also be measured (Lansky score).

• Recurrent disease and sero-negative lymphadenopathic KS seen in young children  has a poor prognosis.
   Post treatment follow-up should be six weekly for the fist year followed by 3-monthly follow-up for the next year then 6-montly to yearly after that

 

Pharmacological management

Vincristine, bleomycin, doxorubicin, paclitaxel, vinorelbine, etoposide, vinblastine, irinotecan. 

In resource limited settings, a combination of bleomycin and vincristine is the treatment  of choice.

In failing treatment, doxorubicin can be added to the combination.

Prognosis

Usually very good for HIV infected patients on concurrent antiretroviral medicines (ARVs).

References

  1.  Parkin, D.M., et al. International Incidence of Childhood Cancer. IARC Scientific Publication, No 144
  2.  Nasti G et al. AIDS-related Kaposi’s Sarcoma. J Clin Oncol 2003:21:2876-2882.
  3.  Molyneux E et al. Management of Children with Kaposi ’s sarcoma in  Resource Limited Settings. (accepted for publication in Pediatric Blood &  Cancer 2013)
  4.  Mosam A et al. Kaposi’s sarcoma in sub-Saharan Africa. Curr Opin Infect Dis 2010:23:119-123.

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